PO Condition currency for freights and insurance

Dear All,

In case of Import POs

we are maintaining doc currency in USD in PO header as currency of goods supplier

but we are also maintaing the forwarder chages and duty clearance charges for other vendor BUT with indian Rupees

so please guide me how to maintain the condition of customs duty in INR and how to make MIRO for the same coz ....i am not able to change currecy in miro for the conditions.

Regards,

Vimlesh